In the prior art, metal suspensions in insulating fluids were studied as a factor in the electrical breakdown of insulating fluids. A spark discharge momentarily appears as metal contacts immersed in oil, and carrying an electric current, are separated. Metal particle suspensions are produced by condensation of metal vapors from the spark discharge in the oil, wherein the metal particle are usually spherical in shape. Prior art in this field is summarized in the book Electrical Breakdown in Insulating Fluids, by J. A. Kok, Interscience 1961. In this book, Coehn's Rule is given, which states that high permittivity materials (metals, carbon, etc.) in insulating fluids become positively charged. This occurs by the emission of electrons from the materials into the fluid. It is stated that suspensions of small particles, between 50 and 3000 .ANG. are stable, but that larger particles are not stable and flocculate and settle. The stability of metal suspensions in insulating fluids is related to surface-active agents, such as soaps, which surround the metal and form a charged double layer. The charged atmospheres of the double layers from a repelling barrier which prevents the metal particles from contacting each other. The thickness of the double layer is said to be about 20 .ANG., and the distance over which the repulsion barrier acts not more than 100 .ANG.. In an electric field, metal or carbon particles suspended in a fluid were shown to form into lines parallel to the field direction and were termed "pearl strings" herein termed "particle strings". Experimentally, metals, graphite, molybdenum disulfide, and Herapathite particles were found to have positive, negative or no charges in an insulating fluid, depending on the ionic and chemical nature of the fluid, and the particle chemistry and size.
In the prior art, graphite suspensions were tested as electrodichroic fluids but were not successful because the electrooptical properties of these graphite suspensions were of a small magnitude. Moreover, the stability was unsatisfactory for commercial applications because the existence of the electroordered structure, and the critical ranges of parameters needed for its formation, herein disclosed, were previously unknown.